The present invention relates to a nonaqueous electrolyte battery, and more particularly relates to a nonaqueous electrolyte battery having high heat dissipation characteristics.
In recent years, reduction in size and weight of mobile information terminals, such as a mobile phone, a notebook type personal computer, and a personal digital assistant (PDA), has been rapidly advanced, and hence batteries used as a drive power source therefor are strongly desired to have a higher capacity. Since having a high energy density and a high capacity, nonaqueous electrolyte batteries represented by a lithium ion secondary battery have been widely used as a drive power source for the mobile information terminals mentioned above.
Technical development on the safety of a related lithium ion battery has been carried out in consideration of the cases of various incorrect uses. In view of suppression of heat generation, the above technical development can be further roughly categorized into two types, that is, an improvement in properties of battery materials and an improvement in structure and mechanism of batteries. The development of a flame retardant electrolyte, the use of positive and negative active materials which generate a small amount of heat, and the like are categorized into the former group, and the prevention of overcharge and over-discharge by an external protective circuit, the reduction in inside pressure by a safety valve in gas ejection, and the like are categorized into the latter group.
For example, as disclosed in Japanese Unexamined Patent Application Publication No. 2002-208439, as for the structure to improve the heat conduction, a technique in which an anode or a cathode is thermally contacted to a metal package has been proposed.